1. Field of the Invention
Example embodiments relate to a thin film transistor (TFT), and more particularly, to an oxide TFT having a top gate structure and to a method of manufacturing the same.
2. Description of the Related Art
In an active matrix type flat panel display (FPD), e.g., a liquid crystal display (LCD), an organic light emitting display, etc., at least one TFT may be provided in each pixel.
The conventional TFT may include a channel region, an active layer that provides a source region and a drain region, and a gate electrode formed on the channel region to be electrically insulated from the active layer by a gate insulating layer. The active layer of the TFT may be formed of a semiconductor layer, e.g., amorphous silicon or polycrystalline silicon.
However, when the active layer is formed of the amorphous silicon, mobility may be low, so high speed operation of a driving circuit may be difficult to realize. On the other hand, when the active layer is formed of the polycrystalline silicon, while mobility may be high, a threshold voltage may be non-uniform due to the polycrystalline structure.
Further, a method of manufacturing the conventional TFT using low temperature poly-silicon (LTPS) may include an expensive price process, e.g., a laser heat treatment, which may be difficult to control. Therefore, it may be difficult to apply the conventional method to a large area substrate.